Iconv fails to convert to/from UCS-4 (and some other
encodings that may include null bytes).

This is because it is using strlen to determine the
length of a string (both on the input and the output).
Instead it should use the internal length (Z_STRLEN_PP)
for the param to iconv.
The length (calculated from value returned by iconv)
should be used for the result(use RETVAL_STRINGL).

Attched diff is for 4.0.6 (4.1.1 is similar except
for small style changes).
Other changes in the patch are:
a. php_iconv_string made static.
b. Fix compile warning with glibc-2.2.4 - Param to
   iconv is "char **" and not "const char **" (thogh
   the second makes more sense).

-int php_iconv_string(char *, char **, char *, char *);
+static int php_iconv_string(char *, unsigned int, char 
**, unsigned int *, char *, char *);

 PHP_INI_BEGIN()
         STD_PHP_INI_ENTRY("iconv.input_encoding",        
ICONV_INPUT_ENCODING,    PHP_INI_ALL, OnUpdateString,  
input_encoding,        zend_iconv_globals,  iconv_globals)
@@ -111,20 +111,23 @@
        DISPLAY_INI_ENTRIES();
 }

-int php_iconv_string(char *in_p, char **out, char 
*in_charset, char *out_charset)
+static int php_iconv_string(char *in_p, unsigned int 
in_len,
+                        char **out, unsigned int *out_len,
+                    char *in_charset, char *out_charset)
 {
-    unsigned int in_size, out_size;
+    unsigned int in_size, out_size, out_left;
     char *out_buffer, *out_p;
     iconv_t cd;
     size_t result;
     typedef unsigned int ucs4_t;

-    in_size  = strlen(in_p) * sizeof(char) + 1;
-    out_size = strlen(in_p) * sizeof(ucs4_t) + 1;
+    in_size  = in_len;
+    out_size = in_len * sizeof(ucs4_t) + 1;

     out_buffer = (char *) emalloc(out_size);
        *out = out_buffer;
     out_p = out_buffer;
+       out_left = out_size;

     cd = icv_open(out_charset, in_charset);

@@ -135,14 +138,16 @@
                return FAILURE;
        }

-       result = icv(cd, (const char **) &in_p, &in_size, 
(char **)
-                                  &out_p, &out_size);
+       result = icv(cd, (char **) &in_p, &in_size, (char 
**)
+                                  &out_p, &out_left);

     if (result == (size_t)(-1)) {
-                efree(out_buffer);
+               efree(out_buffer);
                return FAILURE;
     }

+       *out_len = out_size - out_left;
+
     icv_close(cd);

     return SUCCESS;
@@ -155,6 +160,7 @@
 {
     zval **in_charset, **out_charset, **in_buffer;
        char *out_buffer;
+       unsigned int out_len;

     if (ZEND_NUM_ARGS() != 3 || zend_get_parameters_ex(3, 
&in_charset, &out_charset, &in_buffer) == FAILURE) {
         WRONG_PARAM_COUNT;
@@ -164,8 +170,10 @@
     convert_to_string_ex(out_charset);
     convert_to_string_ex(in_buffer);

-       if (php_iconv_string(Z_STRVAL_PP(in_buffer), 
&out_buffer, Z_STRVAL_PP(in_charset), 
Z_STRVAL_PP(out_charset)) == SUCCESS) {
-               RETVAL_STRING(out_buffer, 0);
+       if (php_iconv_string(Z_STRVAL_PP(in_buffer), 
Z_STRLEN_PP(in_buffer),
+                                        &out_buffer, 
&out_len,
+                                                
Z_STRVAL_PP(in_charset), Z_STRVAL_PP(out_charset)) == 
SUCCESS) {
+               RETVAL_STRINGL(out_buffer, out_len, 0);
        } else {
                RETURN_FALSE;
        }
@@ -178,6 +186,7 @@
 {
        char *out_buffer;
        zval **zv_string, **zv_status;
+       unsigned int out_len;
        SLS_FETCH();
        ICONVLS_FETCH();

@@ -189,10 +198,11 @@
        convert_to_long_ex(zv_status);

        if (SG(sapi_headers).send_default_content_type &&
-               php_iconv_string(Z_STRVAL_PP(zv_string), 
&out_buffer,
+               php_iconv_string(Z_STRVAL_PP(zv_string), 
Z_STRLEN_PP(zv_string),
+                                                
&out_buffer, &out_len,
                                                 
ICONVG(internal_encoding),
                                                 
ICONVG(output_encoding))==SUCCESS) {
-               RETVAL_STRING(out_buffer, 0);
+               RETVAL_STRINGL(out_buffer, out_len, 0);
        } else {
                zval_dtor(return_value);
                *return_value = **zv_string;